float_format string error

[quebbs]

The float_format string works for single values i.e. float_format='%.1f', but it does not appear to work for a formatted string of columns. For example, If I had four columns with increasing significant digits, separated with tabs:

fmt_string='%.1f\t%.2f\t%.3f\t%.4f'

Then for some DataFrame X, I should be able to use:

X.to_csv('./out.txt',float_format=fmt_string,index=False)

But it unfortunately balks at me:

TypeError: not enough arguments for format string

[jreback]

see #4668

I think there is a wish to support a float_format=dict_of_formatters, but it is not implemented
want to submit a pull-request?